Yoast SEO Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the Yoast SEO plugin for WordPress, affecting all versions through 27.1.1. The issue arises from inadequate input sanitization and output escaping, allowing authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts. These scripts are executed when a user accesses the compromised page.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the page.

Reproduction

To reproduce this vulnerability, an authenticated user with Contributor-level access or higher can inject scripts through the 'jsonText' block attribute of the 'How-To' block in the Gutenberg editor. The injected script will be executed when the page is viewed.

Remediation

Users are advised to update the Yoast SEO plugin to version 27.2 or later.